Organic matter and dissolved metallic compounds are found in wastewater and must be treated. The contaminants may be oxidized, a Fenton reagent, that is known as a solution of ferrous iron with hydrogen peroxide, Fe2+/H2O2, can perform these types of oxidation reactions.
The preparation of the Fenton reagent Fe2+/H2O2 is generally accomplished by mixing ferrous sulphate and hydrogen peroxide. The oxidation reaction efficiency is controlled by the ratio of H2O2 to Fe2+. The procedure of preparing the Fenton reagent is relatively complicated and requires pumps, dosing systems and numerous tanks. This type of equipment requires exacting procedures, trained personnel leading to higher labour cost and operating cost.
Furthermore, although effective the use of hydrogen peroxide has a variety of drawbacks. Hydrogen peroxide is most commonly found in aqueous solutions. Low concentrations, of 6 wt. % H2O2 or less in water are widely available. However, higher concentrations of hydrogen peroxide are preferred for Fenton reagents.
These higher concentrations may be hazardous and require a clear understanding of the safety issues relating to hydrogen peroxide. Specifically, at higher concentrations H2O2 is corrosive, a strong oxidizer and dangerous to the health of individuals if incorrectly used, manipulated and/or stored.
High-concentration hydrogen peroxide streams, typically above 40 wt. %, are considered hazardous and require special storage and handling facilities, that are costly, both from a fixed cost and operational cost point of view. Hydrogen peroxide must be carefully stored in well-ventilated areas and away from other flammable materials. Under some circumstances hydrogen peroxide is highly explosive.
On the other hand, Fe2+ is generally used as a ferrous sulfate solution, which has also some drawbacks (mixing, handling, storing the ferrous sulfate chemical).
With an increasing need to decontaminate wastewater there is a need for a Fenton reagent system that eliminates or significantly reduces the challenges associated with high concentrations of liquid hydrogen peroxide solution and handling, mixing and storage of chemicals.